General Description
The MAX1658/MAX1659 linear regulators maximize
battery life by combining ultra-low supply currents
and low-dropout voltages. They feature Dual Mode™
operation, which presets the output to 3.3V (MAX1658) or
5V (MAX1659), or permits it to be adjusted between 1.25V
and 16V. The regulator supplies up to 350mA, with a
typical dropout of 650mV for the MAX1658 and 490mV for
the MAX1659. With their p-channel MOSFET pass transis-
tor, these devices maintain a low quiescent current from
zero output current to the full 350mA, even in dropout.
They support input voltages ranging from 2.7V to 16.5V.
The MAX1658/MAX1659 feature a 1μA shutdown mode,
reverse-battery protection, short-circuit protection, and
thermal shutdown. They are available in a special high-
power (1.2W), 8-pin SO package designed specifically for
compact applications.
Applications
●Digital Cordless Phones
●PCS Phones
●Cellular Phones
●PCMCIA Cards
●Modems
●Hand-Held Instruments
●Palmtop Computers
●Electronic Planners
Features
●Wide Input Voltage Range: 2.7V to 16.5V
●Low, 490mV Dropout at 350mA Output Current
(MAX1659)
● 30μA Supply Current
● 1μA Max Shutdown Current
●High-Power (1.2W) 8-Pin SO Package
●Dual Mode Operation Output:
• Fixed 3.3V (MAX1658)
• Fixed 5.0V (MAX1659)
or Adjustable (1.25V to 16V)
●Thermal-Overload Protection
●Current-Limit Protection
●Reverse-Battery Protection
Dual Mode is a trademark of Maxim Integrated Products.
19-1263; Rev 1; 5/14
*Dice are tested at TA = +25°C, DC parameters only.
+Denotes a lead(Pb)-free/RoHS-compliant package.
PART TEMP RANGE PIN-PACKAGE
MAX1658C/D 0°C to +70°C Dice*
MAX1658ESA+ -40°C to +85°C 8 SO
MAX1659C/D 0°C to +70°C Dice*
MAX1659ESA+ -40°C to +85°C 8 SO
IN
SHDN
OFF
ON
INPUT
UP TO 16.5V
OUTPUT
3.3V OR 5V,
OR ADJ. (DOWN TO 1.25V);
UP TO 350mA
GND SET
OUT
MAX1658
MAX1659
IN
OUTOUT
1
2
8
7
GND
INSHDN
IN
SET
SO
TOP VIEW
3
4
6
5
MAX1658
MAX1659
MAX1658/MAX1659 350mA, 16.5V Input,
Low-Dropout Linear Regulators
Typical Operating Circuit Pin Conguration
Ordering Information
IN to GND ............................................................... -17V to +17V
Continuous Output Current ..............................................500mA
Output Short-Circuit Duration ........................................... Infinite
SET, SHDN to GND ...............................................-17V to +17V
OUT to GND .............................................. -0.3V to (VIN + 0.3V)
Continuous Power Dissipation (Note 1)
SO (derate 14.5mW/°C above +70°C) ............................1.2W
Operating Temperature Range
MAX1658ESA/MAX1659ESA ......................... -40°C to +85°C
Junction Temperature ...................................................... +150°C
Storage Temperature Range ............................ -65°C to +160°C
Lead Temperature Range (soldering, 10sec) .................. +300°C
(VIN = 5V (MAX1658), VIN = 6V (MAX1659); COUT = 10μF; SHDN = IN; TA = TMIN to TMAX; unless otherwise noted. Typical values
are at TA = +25°C.) (Note 2)
Note 1: See Operating Region and Power Dissipation section.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Input Voltage Range VIN SET = OUT 2.7 16.5 V
Output Voltage VOUT
SET = GND,
0mA < ILOAD < 350mA
MAX1658,
5V ≤ VIN ≤ 16.5V 3.20 3.30 3.40
V
MAX1659,
6V ≤ VIN ≤ 16.5V 4.85 5.00 5.15
Regulated Output Voltage Range (Note 3) 1.25 16 V
Maximum Output Current IOUT(MAX) 350 mA
Current Limit ILIM 900 mA
Supply Current IQ30 60 μA
Dropout Voltage (Note 4) ΔVDO
IOUT = 1mA 2
mV
IOUT = 350mA MAX1658 650 1500
MAX1659 490 875
Line Regulation ΔVLNR
MAX1658, VIN = 5V to 16.5V 0.03 %/V
MAX1659, VIN = 6V to 16.5V 0.05
Load Regulation ΔVLDR IOUT = 0mA to 350mA 0.003 %/mA
Startup Overshoot VOSH 0 %VOUT
Output Noise en10Hz to 100kHz 2.5 mVP-P
SHUTDOWN
Logic-Low Input VINLSHDN 2.7V ≤ VIN ≤ 16.5V 0.4 V
Logic-High Input Threshold VINHSHDN 2.7V ≤ VIN ≤ 16.5V 2.0 V
Shutdown Input Bias Current ISHDN SHDN = GND or SHDN = IN 0.1 μA
Shutdown Supply Current IQSHDN SHDN ≤ 0.4V 0.1 1 μA
Shutdown Exit Time tSTART VOUT = 5.0V 120 μs
MAX1658/MAX1659 350mA, 16.5V Input,
Low-Dropout Linear Regulators
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Absolute Maximum Ratings
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these
or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect
device reliability.
Electrical Characteristics
(VIN = 5V (MAX1658), VIN = 6V (MAX1659); COUT = 10μF; SHDN = IN; TA = TMIN to TMAX; unless otherwise noted. Typical values
are at TA = +25°C.) (Note 2)
Note 2: Specifications to -40°C are guaranteed by design, not production tested.
Note 3: Adjustable configuration only. VIN = 16.5V.
Note 4: The dropout voltage is defined as (VIN - VOUT) when VOUT is 100mV below the value of VOUT for VIN = VOUT + 2V.
(VIN = 5V (MAX1658), VIN = 6V (MAX1659); SHDN = IN; SET = GND; CIN = 0.1μF; COUT = 10μF tantalum; TA = +25°C; unless
otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
SET INPUT
SET Reference Voltage VSET IOUT = 10μA (Note 3) 1.174 1.210 1.246 V
SET Input Leakage Current ISET
TA = +25°C (Note 3) 0.01 0.025 μA
TA = +85°C (Note 3) 0.1
THERMAL PROTECTION
Thermal Shutdown Temperature TSD 165 °C
Thermal Shutdown Hysteresis ΔTSD 10 °C
-8
-72
10 1000 10k100 100k
MAX1659
POWER-SUPPLY
REJECTION RATIO vs. FREQUENCY
-56
-64
MAX1658 toc03
FREQUENCY (Hz)
PSSR (dB)
-48
-32
-40
-24
-16
VIN = 6.15V TO 6.4V
VOUT = 5V
-10
-90
10 1000 10k100 100k
MAX1658
POWER-SUPPLY
REJECTION RATIO vs. FREQUENCY
-70
-80
MAX1658 toc01
FREQUENCY (Hz)
PSRR (dB)
-60
-40
-50
-30
-20
VIN = 5.2V TO 5.4V
VOUT = 3.3V
MAX1658/MAX1659 350mA, 16.5V Input,
Low-Dropout Linear Regulators
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Electrical Characteristics (continued)
Typical Operating Characteristics
(VIN = 5V (MAX1658), VIN = 6V (MAX1659); SHDN = IN; SET = GND; CIN = 0.1μF; COUT = 10μF tantalum; TA = +25°C; unless
otherwise noted.)
0
20
40
60
80
0 3 6 9 1512 18
MAX1658
SUPPLY CURRENT vs. INPUT VOLTAGE
MAX1658/59 toc06
INPUT VOLTAGE (V)
SUPPLY CURRENT (µA)
IL = 100mA
IL = 0mA
VOUT = 3.3V
0
40
80
100
20
60
120
140
0 100 200 300 40050 150 250 350
QUIESCENT CURRENT
vs. LOAD CURRENT
MAX1658/59 toc09
LOAD CURRENT (mA)
QUIESCENT CURRENT (µA)
0
500
1000
1500
2000
0 3 6 9 12 15
DROPOUT VOLTAGE
vs. OUTPUT VOLTAGE
MAX1658/59 toc07
OUTPUT VOLTAGE (V)
DROPOUT VOLTAGE (mV)
IL = 350mA
0
200
400
600
100
300
500
700
800
0 100 200 300 400
DROPOUT VOLTAGE
vs. LOAD CURRENT
MAX1658/59 toc08
LOAD CURRENT (mA)
DROPOUT VOLTAGE (mV)
VOUT = 5.0V
VOUT = 3.3V
B
A
100µs/div
MAX1658
LINE-TRANSIENT RESPONSE
MAX1658/59 toc11
A: INPUT VOLTAGE (1V/div), VIN = 6V (HIGH), VIN = 5V (LOW)
B: OUTPUT VOLTAGE (100mV/div)
VOUT = 3.3V
B
A
MAX1659
LINE-TRANSIENT RESPONSE
MAX1658/59 toc10
A: INPUT VOLTAGE (1V/div), VIN = 7V (HIGH), VIN = 6V (LOW)
B: OUTPUT VOLTAGE (100mV/div)
100µs/div
VOUT = 5.0V
0.990
0.994
0.992
0.996
0.998
1.000
0100 200 300 400
NORMALIZED OUTPUT VOLTAGE
vs. LOAD CURRENT
MAX1658/59 toc05
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE V
NOMINAL
/V
OUT
(V)
3.3V OUTPUT
5V OUTPUT
B
A
VOUT = 3.3V
MAX1658
LOAD-TRANSIENT RESPONSE
MAX1658/59 toc13
A: OUTPUT VOLTAGE (100mV/div)
B: IOUT = 300mA (HIGH), IOUT = 40mA (LOW)
200µs/div
B
A
VOUT = 5V
MAX1659
LOAD-TRANSIENT RESPONSE
MAX1658/59 toc12
A: OUTPUT VOLTAGE (100mV/div)
B: IOUT = 300mA (HIGH), IOUT = 40mA (LOW)
200µs/div
MAX1658/MAX1659 350mA, 16.5V Input,
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Typical Operating Characteristics (continued)
(VIN = 5V (MAX1658), VIN = 6V (MAX1659); SHDN = IN; SET = GND; CIN = 0.1μF; COUT = 10μF tantalum; TA = +25°C; unless
otherwise noted.)
PIN NAME FUNCTION
1 SET Output-Voltage Input. Connecting SET to ground selects the factory-preset 3.3V (MAX1658) or 5V (MAX1659)
output voltage. For an adjustable output voltage, connect SET to a resistive voltage-divider from OUT to GND.
2SHDN Shutdown Input. When SHDN is low, the device turns off and typically draws 0.1μA of supply current.
3, 6, 7 IN Unregulated Input Supply Voltage, 2.7V to 16.5V input range. The IN pins also serve as heatsinks. Connect to
a copper plane to achieve maximum thermal dissipation.
4, 5 OUT
Regulated Output Voltage. Fixed or adjustable from 1.25V to 16V. Sources up to 350mA. For stable operation,
bypass with a 10μF, low-ESR (<0.2Ω) capacitor from OUT to GND. For improved load-transient response, use
a larger low-ESR capacitor.
8 GND Ground
B
A0V
3.3V
100µs/div
MAX1658 OVERSHOOT AND
TIME EXITING SHUTDOWN
MAX1658/59 toc14
A: OUTPUT VOLTAGE (1V/div)
B: SHDN PIN VOLTAGE (2V/div)
B
A0V
5V
100µs/div
MAX1659 OVERSHOOT AND
TIME EXITING SHUTDOWN
MAX1658/59TOC15
A: OUTPUT VOLTAGE (2V/div)
B: SHDN PIN VOLTAGE (2V/div)
10ms/div
10Hz TO 100kHz NOISE, VOUT = 5V (1mV/div), IOUT = 165mA
OUTPUT NOISE
104
103
102
10
10 50k
OUTPUT NOISE DENSITY
vs. FREQUENCY
MAX1658 toc02
FREQUENCY (Hz)
OUTPUT NOISE DENSITY (nVRMS/√Hz)
VOUT = 5V
IOUT = 165mA
MAX1658/MAX1659 350mA, 16.5V Input,
Low-Dropout Linear Regulators
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Typical Operating Characteristics (continued)
Pin Description
Detailed Description
The MAX1658/MAX1659 are micropower, low-dropout
linear regulators featuring Dual Mode operation, which
allows them to deliver an adjustable (1.25V to 16.5V) or
preset (3.3V for the MAX1658, 5V for MAX1659) output.
They supply up to 350mA while requiring only 120μA
of supply current (typically 30μA with no load). The
devices include thermal-shutdown circuitry, output current
limiting, a p-channel pass transistor, a Dual Mode compar-
ator, and a feedback voltage-divider. Figure 1 shows the
functional diagram.
The 1.21V reference is connected to the amplifier’s
inverting input. The error amplifier compares this
reference with the selected feedback voltage and ampli-
fies the difference. The error signal applies the drive to the
p-channel pass transistor. If the feedback voltage is lower
than the reference voltage, the transistor’s gate is pulled
lower, increasing output current.
The output voltage is fed back through an internal resistor
network or an external user-selected network. The Dual
Mode comparator examines the voltage at the SET
pin and selects either the internal or external feedback
path. If SET is below 65mV, internal feedback sets the
MAX1658’s output voltage to 3.3V and the MAX1659’s
to 5V. Otherwise, external feedback is used for an
adjustable output between 1.25V and 16.5V. Additional
features include internal current limiting, reverse-battery
protection, thermal-overload protection, and a 1μA
shutdown mode.
Figure 1. Functional Diagram
P
P
OUT
SET
IN
SHDN
MOSFET
DRIVER
WITH
CURRENT
LIMIT
R2
R1
65mV
GND
DUAL-MODE
COMPARATOR
1.21V
REFERENCE
THERMAL
SENSOR
ERROR
AMPLIFIER
MAX1658
MAX1659
MAX1658/MAX1659 350mA, 16.5V Input,
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P-Channel Pass Transistor
The MAX1658/MAX1659 feature an internal p-channel
MOSFET pass transistor. Using a MOSFET provides
several advantages over similar pnp designs, including
lower dropout voltage and extended battery life. Unlike
bipolar transistors, MOSFETs reduce quiescent current,
because they require no base current, particularly at heavy
loads and in dropout. As a result, the MAX1658/MAX1659
operate at a low quiescent current even in dropout.
Output-Voltage Selection
Dual Mode operation allows the MAX1658/MAX1659 to
operate at either a preset or a user-adjustable output
voltage. The device compares the SET pin voltage with
an internal 65mV reference. If the voltage is lower than
65mV (typically achieved by grounding SET), the device
switches to an internal resistor-divider feedback network
that sets the output voltage. The MAX1658’s preset output
voltage is 3.3V and the MAX1659’s is 5V (Figure 2).
If the SET pin is not below 65mV, the device switches to
external feedback and SET becomes a feedback input.
The feedback network can be configured to produce an
output between 16V and the voltage reference (nominally
1.21V). Under regulation, the feedback mechanism
adjusts the error signal such that the voltage at the SET
pin equals the reference voltage. Therefore, to achieve
the minimum output, connect SET directly to OUT. For
other voltages, a resistive voltagedivider network is
necessary. Figure 3 shows the topology of a typical circuit
operating in adjustable mode. The output voltage is set by
the following equation:
OUT SET
R1
V V 1 R2
= +
where VSET = 1.21V. Solving for R1 yields:
OUT
SET
V
R1 = R2 1
V
−
The input leakage current of the SET input is less
than 25nA. This allows the use of large resistors in the
feedback network to minimize output current loss without
compromising accuracy. R2 can be as high as 500kΩ in
most applications.
Shutdown
A logic-low on the SHDN pin places the MAX1658/
MAX1659 in shutdown. This mode deactivates all
functions, including the pass transistor. The device
consumes less than 1μA of supply current in shutdown,
and its output becomes high impedance. The MAX1658/
MAX1659 exit shutdown in 100μs.
Output Current Limit
The MAX1658/MAX1659 include current-limiting circuitry
that monitors and controls the pass transistor and limits
output current to around 900mA. The output can be
shorted to ground indefinitely without damaging the device.
Figure 2. Preset Output Configuration Figure 3. Adjustable Output Configuration Using External
Feedback Resistors
SHDN
24, 5
8 1
3, 6, 7 IN
INPUT
VOLTAGE
ON
OFF
OUTPUT VOLTAGE
3.3V/350mA
(5V/350mA)
10µF
0.1µF
GND SET
OUT
MAX1658
(MAX1659)
IN
3, 6, 7 4, 5
1
8
2SHDN
OUTPUT
VOLTAGE
COUT
10µF
R1
R2
0.1µF
INPUT
VOLTAGE
GND
OUT
SET
VOUT = VSET
(
1 + R1
)
R2
VSET = 1.21V
MAX1658
MAX1659
MAX1658/MAX1659 350mA, 16.5V Input,
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Thermal-Overload Protection
Thermal-overload protection limits total power dissipation
in the MAX1658/MAX1659. When the junction temperature
exceeds TJ = +165°C, the pass transistor deactivates,
allowing the IC to cool. Once it has cooled by 10°C, the
control logic enables operation. Under thermal overload,
the output of the device pulses as the die heats up and
then cools to operational levels. Prolonged operation
under these conditions is not recommended.
Operating Region and Power Dissipation
Maximum power dissipation of the MAX1658/MAX1659
depends on the thermal resistance of the package and
circuit board, the temperature difference between the
die and ambient air, and the rate of air flow. The power
dissipation by the device is P = IOUT (VIN - VOUT). The
maximum power dissipation is:
( )
( )
JA
MAX JB BA
T T
P
−
=
θ +θ
where (TJ - TA) is the temperature difference between
MAX1658/MAX1659 die junction and the surrounding air,
θJB is the thermal resistance of the package, and θBA is
the thermal resistance through the printed circuit board,
copper traces, and other materials to the surrounding
air. The 8-pin SO package for the MAX1658/MAX1659
features a special lead frame with a lower thermal
resistance and higher allowable power dissipation than
a standard 8-pin SO package. The thermal resistance
of this package is θJB = 69°C/W, compared with θJB =
170°C/W for a standard 8-pin SO package.
The IN pins of the MAX1658/MAX1659 package perform
the dual function of providing an electrical connection to
IN and channeling heat away. Connect all IN pins to the
input voltage using a large pad or power plane on the
surface. Where this is impossible, connect to a copper
plane on an adjacent layer. The pad should meet the
dimensions specified in Figure 4.
Figure 4 assumes the IC is soldered directly to the pad,
has a +125°C maximum junction temperature and a +25°C
ambient air temperature, and has no other heat sources.
Use larger pad sizes for lower junction temperatures,
higher ambient temperatures, or conditions where the IC
is not soldered directly to a heat-sinking IN pad.
The MAX1658/MAX1659 can regulate currents up to
350mA and operate with input voltages up to 16.5V,
but not simultaneously. High output currents can only
be sustained when input-output differential voltage is
low, as shown in the following equation. Maximum
power dissipation depends on packaging, board layout,
temperature, and air flow. The maximum output current is:
( )
( )
MAX A
OUT(MAX) IN OUT
P 125 C T
I V V 100 C
× °−
=− ×°
where PMAX is derived from the TJ = 125°C curve of
Figure 4.
Reverse-Battery Protection
The MAX1658/MAX1659 feature reverse-battery
protection. Under normal operation, a p-channel MOSFET
connects the substrate of the device to IN. When the input
voltage falls below ground (implying reverse-battery
conditions), the p-channel switch turns off and
disconnects the substrate from IN, disabling the device.
The maximum reverse-battery voltage allowed is -17V.
SHDN also withstands reverse-battery conditions and
can be connected directly to IN with no loss of protection.
Polarized input bypass capacitors become damaged
under reverse-battery conditions. To ensure circuit
reliability, use a nonpolarized capacitor at the input.
The MAX1658/MAX1659 do not provide reverse-current
protection. If VOUT is greater than VIN by more than
300mV, reverse current flows. Reverse-current protection
can be added by connecting a Schottky diode in series
with IN.
Figure 4. Typical Maximum Power Dissipation vs. Ground Pad
Area
1600
1400
1200
1000
800
600
400
0.1
0.65
1
6.5
COPPER GROUND PAD AREA
10 (in2)
65 (cm2)
POWER DISSIPATION (mW)
Tj = +125°C
Tj = +85°C
SINGLE-SIDED 1oz. COPPER
TA = +25°C, STILL AIR
MAX1658/MAX1659 350mA, 16.5V Input,
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Applications Information
Output Capacitor Selection and Stability
To maintain stability, connect a ≥10μF capacitor with less
than 200mΩ equivalent series resistance (ESR) from
OUT to GND. Larger output capacitors improve load-
transient response. Currents lower than 350mA make the
use of smaller output capacitors possible. Table 1 shows
the maximum output current typically achieved using
various output capacitors. Output voltages higher than
3.3V require less output capacitance to remain stable.
Input Bypass Capacitor
The use of a 0.1μF to 10μF input bypass capacitor is
recommended. Larger capacitors provide better supply
noise rejection and line-transient response, as well as
improved performance when the supply has a high AC
impedance. Polarized input bypass capacitors become
damaged under reverse-battery conditions. If reverse
input voltages are expected, use a nonpolarized capacitor
at the input.
Noise and PSRR
The MAX1658/MAX1659 exhibit 2.5mVp-p of noise during
normal operation. This noise level is negligible in most
applications.
The MAX1658/MAX1659 are designed to maintain
excellent power-supply rejection (55dB) at 50Hz/60Hz
(or 50dB at 120Hz). These regulators are ideal for wall-
cube applications that may contain significant ripple.
Larger input and output capacitors further improve the
circuit’s AC response. See the Power-Supply Rejection
Ratio vs. Frequency graphs in the Typical Operating
Characteristics.
Table 1. Typical Load Current Capabilities
OUTPUT CAPACITOR LOAD CURRENT RANGE
2.2μF tantalum 0mA to 120mA
4.7μF tantalum 0mA to 250mA
10μF tantalum 0mA to 350mA
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
8 SO S8+10F 21-0041 90-0096
MAX1658/MAX1659 350mA, 16.5V Input,
Low-Dropout Linear Regulators
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Package Information
For the latest package outline information and land patterns
(footprints), go to www.maximintegrated.com/packages. Note
that a “+”, “#”, or “-” in the package code indicates RoHS status
only. Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
Chip Information
TRANSISTOR COUNT: 207
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
1 5/14 Added lead(Pb)-free OPNs to Ordering Information and rebranded data sheet 1–12
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
MAX1658/MAX1659 350mA, 16.5V Input,
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Revision History
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